Dryvlyne

I'm curious, how much does reduced bike weight translate into a speed increase?

If anyone knows of a study that looks specifically at this I'd be very interested in that. Otherwise just anecdotal feedback from users that have gone to a lighter bike would be great; how much did your avg pace improve?

rpenmanparker 

"Say is ain't so, Joe."

JerrySTL

I have a nice CF road bike and a steel touring bike that weighs about 10 lbs more. I'm about 2-3 mph faster on the road bike on flat roads. In the hills I'm even slower on the touring bike.

However the touring bike has much fatter tires (700x32 vs 700x25) which along with the wider wheels makes the bike not as aerodynamic. Speaking of aerodynamics, I sit much more upright on the touring bike.

Therefore while I think that the weight slows me down, it's probably only a part of the issue.

rpenmanparker 

I have ridden aluminum, steel (several), titanium and carbon fiber ranging from 13.5 to 22.0 lb. All similar geometry road bikes. NO difference in speed at all, ever.

asgelle

Analytic Cycling, Interactive methods for estimating cycling performance.

asgelle

Unless you're dialing back your power as weight goes down, there most certainly is a difference in speed. Now whether you or whatever you're using to measure are sensitive enough to notice is another question.

Dryvlyne

@asgelle - that is a great link, thanks for sharing! I'm definitely looking forward to digging into that more tonight.

merlinextraligh

There are a number of online calculators that answer this question. 2 lbs weight difference on flat ground, the difference will be extremely small.

With lots of accelerations (like in a crit) it would make a very small difference.

Sustained climbs the 2lbs would be worth a couple of seconds a mile.

There is a real and measurable difference, buts so small as to be almost imperceptible.

Dryvlyne

@merlinextraligh - let me ask this then, at what weight difference would you consider it worthy of upgrading your bike if you simply wanted to help improve your pace?

I know this is comparing apples to oranges but when I switched from an MTB to road bike my pace improved dramatically given similar conditions (I was riding the MTB on the road). Now that I'm on an actual road bike I'm trying to ascertain at what point it makes sense to upgrade to a newer bike provided that I'm as well conditioned as I can be physically. The most logical thing for me to first consider was the weight of the bike but I'm sure there are other factors as well.

dr_lha

This is a pretty good article on how much speed a lighter bike really gets you. Of course this is comparing bikes that are all pretty light to start with:

Bike Weight and the Myth of Fast Bikes - usatriathlon.org

svtmike

I believe this observation for a Houston (flat as a pancake terrain) rider.

10 Wheels

Same for me...

topflightpro

Were you riding MTB tires? If so, your speed increase likely had more to do with the change in tires than the reduction in weight of bicycles. Narrower road tires are just faster on the road than wider MTB tires, especially if they weren't slicks.

fa63

I am just as fast on my 16 lbs titanium Seven as I am on my 19 lbs aluminum Giant and steel Zanconato. They have essentially identical contact points (so the fit between them is essentially identical), and use similar tires (25 mm high quality clinchers). I live in Atlanta, and most of the routes I use are pretty hilly (about 60-80 ft elevation gain per mile).

Drew Eckhardt 

I weigh 138 pounds, have an FTP of at least 210 Watts, and that combination is good for about 22MPH on flat ground in a straight line or 20 once you throw in bumps and turns around which you can't pedal.

Analytic Cycling Speed Given power agrees - try .4 m^2 Sd, .760 Cd from Gibertini and Grassi's paper, 71.2 kg, and .004 Crr which is close for nice tires - 9.93 m/s, 22.2 MPH

On a 6% climb that's 4.35 meters/second, 9.7 MPH.

Dropping bike weight to 15 pounds for 69.4 kg total weight would net 9.94 meters/second or 22.2 MPH on flat ground and 4.45 meters/second, 10.0 MPH up-hill. That's a 2.2% speedup and good for 41 seconds an hour on an up-hilll time trial like the Mt. Diablo Challenge.

Heavier riders will see smaller gains.

IOW, for practical values of "lighter" it usually does not matter.

baron von trail 

Hmm, I don't know about weight of the bike, but I know damned sure that I am a lot faster when I weigh 10 lbs less.

indyfabz

There are. I thought everyone knew that, all other thins being equal, red is the fastest color.

indyfabz

Less than what?

ahsposo 

just a little tiny face-palm

merlinextraligh

As for the road to MTB example, you've got 3 things going on in descending order of importance: 1) postion on the bike; you're likely much more aero on the road bike,and that will explain up to a couple of mph difference, 2) Rolling resistance of good road tires, versus fat, knobby MTB tires, this can be as much as a mph or so, 3) Weight, even a 7-10lb weight difference is going only be worth about .1mph on an 8% grade.

So weight is really the smallest part of the equation, and in terms of performance its just not worth worying aobut unless you're racing, and then only if you're losing races by a couple of seconds.

But there are other reasons to get a lighter bike. They feel nicer, they're easier to put up in the garage, and you get to brag about how light your bike is.

I paid a lot of money to get a 13lb pound bike, and I like it a lot, but I'm not deluding myself that it's worth it beause I'm faster on it.

Its worth it because I like how it rides, and looks, and being able to brag about my 13lb bike.

If you're riding a bike that's over 23-24lbs, I think you can make a reasonable case that the weight savings of getting a 17-18 lb bike will result in a noticeable, albeit small improvement, and at not too great a cost.

If you've got an 18 pound bike, and want to go to 15 pounds you'll pay a lot for the privilege.

rpenmanparker 

Same geometry and rider position. Similar rim profiles and tires. No elevation changes. Pretty much steady speed riding. If the difference that you say must be there is that small, why bother to even talk about it.

therhodeo

5mph is my answer.

3alarmer 

...trying to shave some weight on your build ?

3alarmer 

..........don't tell me.........don't tell me..........I know this one....................................is it breadbox ?

merlinextraligh

FTFY. On flat ground, aerodynamics are dramtically more important than weight. 10lbs of weight on the flats, will make a tiny difference in speed. (Small enough, the rounding doesn't show it in Kruezotter). 10lbs on the hills will be noticeable, but we're talking around .1mph. Whereas an upright position on the flats can be as much as 2 miles per hour difference, compared to a more aero position.